In a normal structure of a multi-layer PCB on which a power semiconductor module package is mounted, a plurality of PCBs 1 are stacked one on another as shown in FIG. 1. Each of the PCBs 1 is formed by printing circuit patterns 1b and 1c, made of copper, on both surfaces of a substrate 1a like FR-4, CEM-1, CEM-3, Al METAL-PCB. In addition, the PCBs are electrically insulated from one another by an insulation layer 2 which is made of prepreg and formed between the PCBs.
A power semiconductor module package P may be mounted on the circuit pattern of the outermost PCB 1. In order to discharge heat generated from the power semiconductor module package P, the core C of the power semiconductor module package P is disposed to face the outside (opposite to the PCB 1), and a heat dissipation structure 4 is installed on the outside of the power semiconductor module package P in contact with the core C.
According to such a normal multi-layer PCB structure, however, heat increases as the density of a current flowing through the circuit pattern increases. However, since the PCBs are stacked one on another in sequence, heat generated from the circuit pattern of the PCB located inside is not efficiently discharged and thus there is a great risk of fire. Accordingly, there is a disadvantage that it is impossible to use a high current of about hundreds of amperes to thousands of amperes.
In addition, in order to discharge the heat generated from the power semiconductor module package, the heat dissipation structure 4 should be additionally installed on the outside of the power semiconductor module package as shown in FIG. 1. However, there are disadvantages that the structure of a product becomes complicated due to the heat dissipation structure 4 and it is difficult to realize slimness and high density of a product due to the volume of the heat dissipation structure 4.